Dr. DeFAzio was a faculty member and full professor of Student Services at the City University of New York and is now a Professor Emeritus. He is a licensed psychologist in New York State and a Certified School Psychologist in New York as well as New Jersey. In addition to a doctorate, he received additional training as a graduate of the New Hope Guild Child Center specializing in child and adolescent psychotherapy, and adult therapy at the New York University Postdoctoral Program in Psychotherapy and Psychoanalysis. He has been a senior consulting psychologist to the New York City Police Department and to various civil and religious organizations including the United Nations Security Office. He had served as a consultant to justices of the New York State Supreme Court in matters of disputed child custody, visitation and general child welfare. Dr. DeFazio was a senior consultant to the New York area Vietnam Veteran Outreach Centers and the Department of Veterans Affairs Medical Center's Stress Disorder Treatment units. He authored numerous articles on divorce, marriage, and the etiology and treatment of Stress Disorders and Depression which appeared in the Journal of Psychology, Psychiatry, American Journal of Orthopsychiatry, etc. and various books. He also served as a consultant to the Russian Federation and helped train those working with Russian veterans of the Afghan War. Dr. DeFazio was a member of the Editorial Board of the Journal of Traumatic Stress Studies and the Board of the Brunner/Mazel Psychosocial Stress Series. He has been a consulting editor to the Journal of Family Therapy and Psychological Reports. During the Gulf War (1991-92), he served as the coordinator of Mental Health Services for the Family Services Program of the 77th Army Reserve Command. In this capacity he also was a consultant to the General Staff on matters pertaining to the treatment and prevention of psychiatric casualties. He has worked in an area hospital with the Organ Donor network. In addition, Dr. DeFazio works with attorneys in a forensic capacity in civil and criminal cases dealing with issues of competence to stand trial, liability, competence to administer funds, disability determinations, etc.

Dr. DeFazio maintains a private practice in Great Neck and accepts insurance payments from; GHI, Empire, Emblem, Blue Cross, MHN, Vytra, HIP, Magna Care, Aetna, Select Pro, 1199, MDNY, MultiPlan, Horizon Healthcare, etc. He is eligible to receive payments from Workers Comp in New York State, Medicare and Medicaid.